• 조명전기설비학회논문지
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• 제26권1호
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• pp.44-53
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• 2012

This paper presents a method to calculate the area of vulnerability by using the impedance building algorithm. The installation of DG (Distributed Generation) is one of the countermeasures against voltage sags in power systems. In order to estimate the effect of the DG, the voltage sag assessment should be performed based on the area of vulnerability and system fault statistics. To determine the area of vulnerability, system impedance matrix should be calculated. The calculation of the impedance matrix of large systems is time-consuming task. This paper addresses an effective scheme to calculate the area of vulnerability and system impedance matrix.

• Nuclear Engineering and Technology
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• 제41권5호
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• pp.747-752
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• 2009

A vulnerability assessment is essential for the efficient operation of a physical protection system (PPS). Previous assessment codes have used a simple model called an adversary sequence diagram. In this study, the use of a two-dimensional (2D) map of a facility as a model for a PPS is suggested as an alternative approach. The analysis of a 2D model, however, consumes a lot of time. Accordingly, a generalized heuristic algorithm has been applied to address this issue. The proposed assessment method was implemented to a computer code; Systematic Analysis of physical Protection Effectiveness (SAPE). This code was applied to a variety of facilities and evaluated for feasibility by applying it to various facilities. To help upgrade a PPS, a sensitivity analysis of all protection elements along a chosen path is proposed. SAPE will help to accurately and intuitively assess a PPS.

• Nuclear Engineering and Technology
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• 제54권6호
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• pp.2135-2146
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• 2022

A nuclear energy facility is one of the most critical facilities to be safely protected during and after operation because the physical destruction of its barriers by an external attack could release radioactivity into the environment and can cause harmful effects. The barrier walls of nuclear energy facilities should be sufficiently robust to protect essential facilities from external attack or sabotage. Physical protection system (PPS) vulnerability assessment of a typical small nuclear research reactor was carried out by simulating an external attack with a tri-nitro toluene (TNT) shaped charge and results are presented. The reinforced concrete (RC) barrier wall of the research reactor located at a distance of 50 m from a TNT-shaped charge was the target of external attack. For the purpose of the impact assessment of the RC barrier wall, a finite element method (FEM) is utilized to simulate the destruction condition. The study results showed that a hole-size of diameter 342 mm at the front side and 364 mm at the back side was created on the RC barrier wall as a result of a 143.35 kg TNT-shaped charge. This aperture would be large enough to let at least one person can pass through at a time. For the purpose of the PPS vulnerability assessment, an Estimate of Adversary Sequence Interruption (EASI) model was used, which enabled the determination of most vulnerable path to the target with a probability of interruption equal to 0.43. The study showed that the RC barrier wall is vulnerable to a TNT-shaped charge impact, which could in turn reduce the effectiveness of the PPS.

• 한국지하수토양환경학회지:지하수토양환경
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• 제18권5호
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• pp.26-38
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• 2013

In this study, priority for groundwater contamination management was assessed based on regional vulnerability in Goyang-si area, Gyonggi-do, Korea using analytic hierarchy process (AHP) and geographic information system (GIS). We proposed a concept for regional vulnerability to groundwater contamination with using socio-environmental vulnerability factors, which can be classified into three properties including regional hydrogeological property, contamination property, and groundwater use property. This concept is applied to Goyang-si area. For AHP analysis, an expertise-targeted survey was conducted. Based on the survey, a total of 10 factors (criteria) and corresponding weights for regional vulnerability assessment were determined. The result shows that regional contamination property is the most weighted factor among the three property groups (hydrogeological property: contamination property: groundwater use property = 0.3: 0.4: 0.3). Then, database layers for those factors were constructed, and regional vulnerability to groundwater contamination was assessed by weighted superposition using GIS. Results show that estimated regional vulnerability score is ranged from 22.7 to 94.5. Central and western areas of Goyang-si which have groundwater tables at shallow depths and are mainly occupied by industrial and residential areas are estimated to be relatively highly vulnerable to groundwater contamination. Based on assessed regional vulnerability, we classified areas into 4 categories. Category 1 areas, which are ranked at the top 25% of vulnerability score, take about 2.8% area in Goyang-si and give a high priority for groundwater contamination management. The results can provide useful information when the groundwater management authority decide which areas should be inspected with a high priority for efficient contamination management.

• 한국환경복원기술학회지
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• 제10권6호
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• pp.110-119
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• 2007

This study's objects are to predict distribution and to assess vulnerability of sub-alpine vegetations in the Korean peninsula for climate change using various climate models. This study validates relationship between sub-alpine vegetations and environmental factors using Pearson correlation analysis. Then, the future distribution of sub-alpine vegetations are predicted by a logistic regression. The major findings in this study are; First, spring mean temperature (March-May), total precipitation, elevation and warmth index are highly influencing factors to the distribution of sub-alpine vegetations. Second, the sub-alpine vegetations will be disappeared in South Korea and concentrated around Baekdu Mountain in North Korea. North Korea is predicted to have serious impact of climate change because temperature will be increased higher than in South Korea. The study findings concluded that the assessment of the future vulnerability of sub-alpine vegetations to climate change are significant.

• 한국농공학회논문집
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• 제61권6호
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• pp.41-53
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• 2019

Recently, the damage caused by climate change has been distinguished in the world. The Korean Peninsula is also suffering from drought, so it is necessary to study the vulnerability assessment to identify and predict the state of the irrigation facility, which is a irrigation facility. As the damage caused by drought is occurring in the Korean peninsula, it is necessary to study the vulnerability assessment to know the condition of the irrigation facility, and to predict it. The target areas were Yeongdong-gun, Cheonan-si, Mungyeong-si, Geochang-gun, Muju-gun, and Yeonggwang-gun. The survey items were selected as positive impacts survey items, including precipitation, groundwater level, and pumping capacity per groundwater well. The negative impacts were selected as the cultivation acreage, Number of days without rain, and the ratio of private underground wells. The survey method was investigated by various methods such as "weather data portal", "groundwater level status information", "agricultural drought management system", "groundwater survey yearbook". The results of vulnerability assessment were expressed by the score by conducting survey and standardization. As a result, Yeonggwang-gun showed normal vulnerability, and other areas showed "vulnerable" or "very vulnerable".

• 한국시뮬레이션학회논문지
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• 제30권1호
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• pp.1-9
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• 2021

해상에서 임무를 수행하는 함정은 적의 무장 및 위협에 대응하며 임무를 완수해야 한다. 최근 현대전에서는 적 무장의 치명도가 높아짐에 따라 함정의 생존성이 중요시되고 있다. 함정의 생존성은 전투 상황 하에서 함정이 생존할 수 있는 정도를 지표화 한 것으로, 일반적으로 피격성, 취약성, 그리고 회복성의 세 가지 요소로 구분된다. 함정의 생존성에 대한 연구는 지속적으로 수행되어 왔으며, 생존성의 요소 중 취약성에 대한 국내 연구가 활발히 진행되고 있다. 본 논문에서는 M&S기법을 활용하여 전구급 교전분석을 위한 함정 취약성 평가모델을 개발하였다. 전구급 교전분석을 위해 확률적 접근이 아닌 결정형 전투평가 논리를 적용하였으며, 각 탑재시스템의 특성을 반영하여 피해평가 모의논리를 보다 구체적으로 반영하였다. 각 체계별 탑재장비들의 대표 상태 지수를 도입하여 정량화 된 함정의 상태를 확인하였다. 모의논리 반영여부를 확인하기 위해, 가상의 피해상황들을 설정하고 각 상황에서의 선체 및 탑재장비의 손상률을 분석함으로써 평가모델의 타당성을 확인하였다.

• 한국산학기술학회논문지
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• 제15권11호
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• pp.6877-6883
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• 2014

지속적인 사회발전으로 인하여 호소의 수질오염이 악화되고 있다. 호소의 특성 및 유역의 전반적인 측면에서 수질오염에 따른 호소의 취약성을 평가하기 위해, 본 논문에서는 기후변화 취약성 평가를 이용하여 호소 취약성-탄력성지수(LVRI)를 산정하였다. 금강 수계의 6개 호소에 대하여 취약성평가로 분류되는 3개의 주요 인자인 노출, 민감도, 적응능력을 대표하는 총 11개 세부평가항목들은 선정하였다. 또한, 엔트로피(Entropy) 방법에 의한 가중치를 산정하여 호소 취약성-탄력지수를 산정하였다. 제안된 호소의 취약성 평가방안의 활용성 검토를 위해 가중치 적용 유 무에 따른 취약성 우선순위를 비교 검토하였다. 본 논문에서 선정된 호소의 취약성 우선순위는 장지적인 수질분석 및 수질관리에 도움이 될 것으로 판단된다.

• Earthquakes and Structures
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• 제5권5호
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• pp.571-588
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• 2013

Many of the current buildings in Algeria were built in the past without any consideration to the requirements of the seismic code. Among these buildings, there are a large number of individual houses built in the 1980's by their owners. They are Reinforced Concrete (RC) frame structures with unreinforced hollow masonry infill walls. This buildings type experienced major damage in the 2003 (Algeria) earthquake, generated by deficiencies in the structural system. In the present study, special attention is placed upon examining the vulnerability of RC frame houses. Their situation and their general features are investigated. Observing their seismic behavior, structural deficiencies are identified. The seismic vulnerability of this type of buildings depends on several factors, such as; structural system, plan and vertical configuration, materials and workmanship. The results of the vulnerability assessment of a group of RC frame houses are presented. Using a method based on the European Macroseismic Scale EMS-98 definitions, presented in previous studies, distribution of damage is obtained.

• 한국정보과학회논문지:컴퓨팅의 실제 및 레터
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• 제14권2호
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• pp.246-250
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• 2008

본 논문에서는 네트워크 취약점 분석 결과의 정확성을 향상시키기 위한 방법으로 다양한 취약점 점검 도구를 통합할 수 있는 네트워크 취약점 자동 분석 시스템을 제안한다. 일반적으로 전문가에 의한 수동 점검이 가장 정확한 취약점 점검 방법으로 평가되지만, 복잡하고 규모가 큰 네트워크의 경우 효율적인 취약점 분석을 위해 자동화된 네트워크 취약점 점검 도구를 활용한다. 그런데 취약점점검 도구의 종류에 따라 점검 대상이 다르거나 동일한 점검 대상에 대해서도 점검 항목과 점검 결과가 다를 수가 있어, 상호보완적인 목적으로 몇 개의 취약점 점검 도구를 동시에 사용하는 것이 효과적이다. 그러나 취약점 점검 도구들의 점검 결과에 대한 연관성 분석과 통합 분석에는 사람에 의한 수동적인 분석 작업이 필요하기 때문에, 이것은 상당히 시간 소모적인 작업이 되고 네트워크의 규모에 따라 통합 분석이 불가능하기도 하다. 본 논문에서는 다양한 취약점 점검 도구를 통합할 수 있는 인터페이스를 제공하고, 공통의 점검 정책 수립과 통합 분석의 자동화를 특징으로 하는 네트워크 취약점 통합 분석 시스템을 제안한다.